Considerable progress was made this year in implementing the operation of a new signal processing workstation, permitting more rapid fine-grained analyses of the acoustic structure of a variety of vocalizations, as well as producing artificial sound sequences used in playback experiments. One focus this year was to improve our understanding of how perception of the infant cry and marmoset phee call affects the behavior of listeners. Playback studies using natural and synthetic vocal sequences were conducted, using vocal 'answers' as a measure of interest in the marmoset study, and heart rate change as a measure of interest in the infant cry study using adult human listeners. Additionally, considerable progress was made in developing an assay for LH from urine and blood samples collected from our breeding colony of marmosets. This assay will permit identification of ovulatory cycles in specific individuals, useful both for assessment of breeding success and to correlate with cyclic changes in vocal activity. Significant gender differences were found in the association between reactivity and cry acoustics in human infants, and in the acoustic properties of species-specific territorial vocalizations in adult common marmosets.